In recent years, with an increasing demand for lighting devices and display devices in the market, luminescent materials have become one of the competed hot topics of research and development. So far, a variety of luminescent materials have been developed and utilized, such as organic electroluminescent materials, photoluminescent materials, cathode ray excited luminescent materials, and ultraviolet radiation excited luminescent materials. These different kinds of luminescent materials can be applied in corresponding lighting devices, display devices etc, respectively.
For example, plasma display panel is a kind of novel direct-view type image display device following the development of cathode ray tube and liquid crystal display. Plasma display panel has the advantages of active emitting, high brightness, large viewing angle, high contrast ratio, good color reproduction, abundant gray scale and fast response, and has become an important technology for flat panel display requiring a large panel and a high definition. The luminescent mechanism of plasma display panel is as follows: due to the discharge of an inert gas such as Xe or Xe—He, said inert gas is then turned into a plasma status which emits vacuum ultraviolet radiations at 147 nm and 172 nm which in turn excite the fluorescent powder coated on the inner wall to emit lights of the three primary colors, i.e. red, green and blue. A color display can be achieved by spatial color mixing and circuit control.
Currently, Zn2SiO4:Mn2+ is one of the most commonly used green fluorescent powder in plasma display panel. When excited by vacuum ultraviolet radiations, Zn2SiO4:Mn2+ exhibits excellent brightness, excellent deterioration resistance and fast-to-reach saturated brightness. However, the afterglow period of Zn2SiO4:Mn2+ is too long, which has an adverse effect on fast displayed images. Furthermore, the dielectric constant of Zn2SiO4:Mn2+ is higher than that of the red and blue fluorescent powders used in plasma display panels, and thus a greater inducing voltage is required for driving display devices such as plasma display panel.
Currently, a novel green fluorescent powder is under study in order to meet all the requirements of plasma display panels. Such a novel green fluorescent powder comprises mainly Mn2+ excited aluminate, for example, BaMgAl10O17:Mn2+ fluorescent powder, Ba0.9Mg0.6Mn0.16.8Al2O3 green fluorescent powder and the like. These novel green fluorescent powders have a lower dielectric constant. However, since Mn2+ is used as the activator, these novel fluorescent powders still exhibit a relatively long afterglow period, and the luminescent brightness of these fluorescent powders is relatively low.